1. This function returns the name of a decision variable or constraint of the problem that would be used for matrix exportation. The parameter of this function must be part of the problem — for instance a hidden constraint cannot be assigned a name.

2. This function requires that the matrix has been generated ( e.g. by a call to exportprob or loadprob). When used with a non linear constraint it is further required for the problem to be loaded into the optimiser and the parameter XPRS_loadnames must be true.